SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5db7f9c3f50f313c6df14c211f47ee2bcba349af3c0e42b153e0283564af36a8' 
  AND token = 'CokGsbEOVR0ZWRKkn0Uvimssj2iB/zc/8dFOQ8ORLxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}